Major improvements:
- Add proper DOM tree structure (dom_tree.cpp/h) with hierarchical node representation
- Refactor HTML parser to use DOM tree instead of flat ContentElement structure
- Enhance text renderer with improved inline content handling and UTF-8 support
- Improve browser interactive element tracking with byte-accurate positioning
- Add comprehensive HTML entity decoding (80+ named entities + numeric)
- Enhance form handling with better field tracking and submission
Code quality improvements:
- Fix all compiler warnings (unused parameters/variables)
- Clean build with zero warnings
- Better separation of concerns between parsing and rendering
Testing:
- Add test_table.html for table rendering verification
This change enables better handling of complex HTML structures while
maintaining the Unix philosophy of simplicity and focus.
